CN110029226B - A method for recovering valuable metals from waste ternary lithium ion positive electrode materials - Google Patents

Abstract

The invention discloses a method for recovering valuable metals in waste ternary lithium ion battery powder. First, the waste ternary lithium ion battery powder is put into a pit furnace fed with oxygen for oxidative roasting to obtain roasted products. The content of middle carbon is reduced by more than 99%, then the calcined product is dissolved in the ammonia-ammonium chloride solution system, put into a reaction kettle, and 1.6% hydrazine hydrate is added as a reducing agent, and the pH value of the obtained leachate is adjusted to 8.00 , according to the O/A ratio of 2, it is added to the extractant, wherein the volume fraction of Versatic 911 is 20%, the volume fraction of sulfonated kerosene is 80%, the control reaction temperature is 30 ° C, and the raffinate is obtained by separation after the reaction for 5 minutes. And the organic phase, through 3-stage countercurrent extraction, the extraction rate of cobalt is more than 98%. The equipment used in the invention is simple, the investment and operation cost is low, the process energy consumption is significantly reduced, and the recovery rate of valuable metals is high.

Description

A method for recovering valuable metals from waste ternary lithium ion positive electrode materials

technical field

The invention relates to pyrometallurgy and hydrometallurgy processes in the field of metallurgy, in particular to a method for effectively recovering valuable metals in waste ternary lithium ion positive electrode materials.

technical background

In recent years, with the widespread application of lithium-ion batteries, the number of waste batteries has increased. The main components of lithium-ion batteries include shell, electrolyte, cathode material, cathode material, adhesive, copper foil and aluminum foil. The cathode materials usually contain valuable metal elements such as Li, Co, Ni, and Mn. Among them, Co, as a strategic metal, is the most economical metal element in waste lithium-ion batteries. Therefore, it is of great significance to recover valuable metals from waste ternary lithium-ion battery cathode materials.

At present, the recycling technology of waste ternary lithium-ion battery cathode materials can be divided into three processes: heat treatment, leaching, and separation of valuable metals. The process of heat treatment is mainly to remove insoluble organics, carbon powder, etc. in waste lithium batteries, and to separate electrode materials and current collectors. The heat treatment method currently used is mostly high-temperature vacuum pyrolysis. The leaching process is to dissolve the product obtained after heat treatment, so that the metal elements in the product enter the solution in the form of ions, and then selectively separate and recover the main valuable metals Co, Li, etc. through various separation techniques. The methods of leaching mainly include chemical leaching and biological leaching.

The chemical leaching method is to realize the dissolution and leaching of electrode materials through acid leaching or alkali leaching. Acid leaching generally uses inorganic acids such as HCl, HNO ₃ , H ₂ SO ₄ as leaching agents to directly dissolve and leaching electrode materials. The study found that adding H ₂ O ₂ , Na ₂ S ₂ O ₃ and other reducing agents to the leaching agent can reduce Co ³⁺ to Co ²⁺ which is easier to dissolve in the leaching solution, thereby improving the leaching rate of cobalt (Chen Liang). et al. Separation and recovery of cobalt, nickel and manganese from waste lithium-ion batteries. Chinese Journal of Nonferrous Metals, 2011, 21(5): 1192-1198). However, inorganic acid leaching has the disadvantages of strong acidity of the leaching solution and easy corrosion of equipment. Alkaline leaching usually uses ammonia system to leaching cathode material powder of waste lithium-ion battery (Zheng Xiaohong. Basic research on recycling cathode waste of power battery based on selective leaching of ammonium-ammonia salt system [D]. University of Chinese Academy of Sciences, 2017). Although the leaching of ammonia system has good selectivity for metal ions, the leaching rate of cobalt in ammonia system is not high, and the leaching time is long.

Bioleaching is a method of using microorganisms to separate valuable metals from solids, but currently the most used microbial leaching is leaching, and in recent years, it has also been used in the leaching of waste lithium batteries (Mishra Det al. Bioleaching of metals from spent lithium ion). secondary batteries using Acidithiobacillus ferrooxidans[J]. Waste Management, 2008, 28(2): 333-338). Microbial recycling of waste lithium-ion batteries has the advantages of less acid consumption, low cost, and simple operation, but it also has disadvantages such as long cycle, difficult bacterial culture, easy contamination, and difficult leachate separation.

The separation methods of valuable metal ions in the leachate mainly include precipitation, extraction and other methods. The precipitation method mainly uses NaOH to adjust the pH to about 5.0, which can remove most of Cu, Al, and Ni. After further extraction and impurity removal, 3% H ₂ C ₂ O ₄ and saturated Na ₂ CO ₃ are sequentially added to produce CoC ₂ O ₄ and Li ₂ CO ₃ are precipitated, the recovery rate of Co is higher than 99%, and the recovery rate of Li is higher than 98% (Pan Xiaoyong et al. Recovery and comprehensive utilization of cobalt and lithium in waste lithium-ion batteries [J]. Chinese Journal of Nonferrous Metals, 2013 , (7):2 047-2054). The precipitation method has a large processing capacity and a high recovery rate of main metals. Controlling the pH value can realize the separation of metals, which is easy to realize industrialization. However, the precipitation method is easily interfered by impurity ions, resulting in low product purity. The solvent extraction method uses organic solvents to form stable complexes with the target ions in the leaching solution, and then separates them with an appropriate organic solvent to extract the target metals and compounds. The extraction method usually first uses the extractant P204 to remove impurities and purify the leaching solution, and then uses the extractant P507 to extract and separate Co and Ni, then use H ₂ SO ₄ for back extraction, and finally add Na ₂ CO ₃ to the back extract solution for selective recovery. Li ₂ CO ₃ (Wu Fang et al. Recovery of cobalt and lithium from spent lithium-ion secondary batteries [J]. Chinese Journal of Nonferrous Metals, 2004, 14(4): 697-701).

SUMMARY OF THE INVENTION

In order to overcome the shortcomings of the traditional processing technology of waste ternary lithium ion positive electrode materials, the present invention provides a method for effectively recovering valuable metals in waste ternary lithium ion positive electrode materials. In order to achieve the above purpose, the technical scheme adopted is as follows: the waste ternary lithium ion positive electrode material is subjected to medium-temperature oxidative roasting in a certain flow of oxygen atmosphere, so that the carbon in the waste ternary lithium ion battery positive electrode material is volatilized in the form of carbon dioxide; the roasting product is Leaching is carried out in the ammonia-ammonium solution system, and the valence state of the metal elements in the system is adjusted by adding an appropriate amount of reducing agent, so that the valuable metals such as lithium, nickel, cobalt, manganese, etc. contained in the leaching solution are introduced into the solution; Sodium or hydrochloric acid was used to adjust the pH of the leaching solution, and then the cobalt in the leaching solution was extracted and separated with Versatic911 extractant.

The specific process and technical parameters are as follows:

(1) Oxidative roasting

The waste ternary lithium-ion battery powder is subjected to medium-temperature oxidative roasting in an oxygen atmosphere to realize the recovery of valuable metals. Put the waste ternary lithium-ion battery powder into the pit furnace. First, at room temperature, oxygen is continuously introduced into the pit furnace at a rate of 100-500mL/min for 10min-30min, and then the temperature in the furnace is raised to 500-700℃. After roasting for 30-150 minutes, the carbon of the waste ternary lithium-ion battery powder enters the subsequent absorption bottle in the form of carbon dioxide. After the reaction is completed, the temperature in the furnace is lowered to normal temperature, and the oxygen is turned off to obtain the roasted product.

(2) Reductive leaching

The obtained roasting product is added to the mixed solution of ammonia-ammonium chloride and hydrazine hydrate according to the liquid-solid ratio (the ratio of liquid volume mL to solid weight g) of 2 to 10:1, wherein the concentration of ammonium chloride in the mixed solution It is 1.0～5.0mol/L, the concentration of ammonia water in the mixed solution is 0.40～2.0mol/L, the volume ratio of hydrazine hydrate in the mixed solution is 1.0～5.0%, the control reaction temperature is 55～95 ℃, the reaction After 30-150 minutes, the leaching residue and the leaching solution containing lithium, nickel, cobalt, manganese, iron, aluminum and copper are obtained by filtering and washing.

(3) Extraction and separation

The obtained leaching solution is adjusted to pH value, the pH value of the leaching solution is adjusted to 6-10, and added to the extractant according to the O/A ratio of 0.5-2.5, wherein the volume fraction of Versatic 911 is 5-25%, and the volume fraction of sulfonated kerosene is 5-25%. 65-95%, the control temperature is 20-40 DEG C, the raffinate and the cobalt organic phase are separated after the reaction for 5-25 minutes, and the cobalt organic phase is back-extracted to obtain a cobalt chloride solution.

The oxygen, ammonia, ammonium chloride, hydrochloric acid, sodium hydroxide, hydrazine hydrate and Versatic911 extractant are all industrial grade reagents.

The invention is suitable for treating secondary resources such as waste ternary lithium ion positive electrode materials, and its composition range is (%): Li5.0-10.0, Ni 25.0-35.0, Co 10.0-20.0, Mn 10.0-20.0, Fe 0.1-1.0 , Al 0.1-1.0, Cu 0.01-1.0, C 1.0-5.0.

Compared with the traditional secondary resource recovery technology of waste ternary lithium ion battery positive electrode material, the invention has the following advantages: (1) oxygen is introduced into the roasting process, which can effectively accelerate the oxidative decomposition of organic matter in the waste ternary lithium ion battery positive electrode material , the separation of valuable metals and carbon in waste ternary lithium-ion batteries is realized, and the volatilization rate of carbon in the oxidative roasting process reaches more than 99%; (2) The ammonia water-ammonium chloride solution system reduction leaching can efficiently leaching the carbon in the roasting product. The leaching rates of lithium, nickel, cobalt and manganese are over 96%, 88%, 87% and 87%, respectively, and the metal leaching rate is high. Effectively reduce the valence state of valuable metals and promote the leaching of valuable metals; (4) Compared with the traditional acid leaching and biological leaching processes, the ammonia system has strong selectivity for metal ions, and the corrosion of the equipment is low; (5) Using Versatic 911 to extract cobalt in an ammonia system, the extraction effect is good, and the extraction rate of cobalt through three-stage countercurrent extraction can reach more than 98%.

Description of drawings

Fig. 1: The process flow schematic diagram of the present invention.

Detailed ways

Example 1

Waste ternary lithium ion battery cathode material, its main components are (%): Li 5.31, Ni 28.35, Co10.35, Mn 13.17, Fe 0.26, Al 0.71, Cu 0.05, C 2.11; industrial grade oxygen, of which O ₂ content ≥99.5%; technical grade ammonium chloride, of which NH ₄ Cl content ≥ 99.5%; technical grade ammonia water, of which NH ₃ ·H ₂ O content is 25-28%; technical grade hydrazine hydrate, of which N ₂ H ₄ ·H ₂ O content is 80%, industrial grade sodium hydroxide, of which NaOH ≥ 96%; industrial grade hydrochloric acid, of which HCl content is 36-38%; industrial grade Versatic 911, of which Versatic 911 content ≥ 99%.

Weigh 10.00g of the waste ternary lithium-ion battery powder of the above-mentioned components, add it to the quartz crucible, place the quartz crucible in the roasting furnace, seal the roasting furnace and start to introduce oxygen, and control the oxygen flow rate to be introduced to be 500mL/min, normal temperature After being fed with oxygen for 15min, the roaster was heated to 650°C. After 90min of reaction, the temperature was cooled down. When the temperature in the furnace was lowered to normal temperature, the feeding of oxygen was stopped. The percentages are expressed as (%): Li 5.50, Ni 29.38, Co 10.73, Mn 13.65, Fe 0.27, Al 0.74, Cu 0.05, C 0.008. The volatilization rate of carbon was 99.65%.

Get above-mentioned roasting product 5g, be 6:1 join in the mixed solution of ammonia-ammonium chloride and hydrazine hydrate according to liquid-solid ratio (the ratio of liquid volume mL and solid weight g), wherein the concentration of ammonium chloride in the mixed solution It is 5.0mol/L, the concentration of ammonia water in the mixed solution is 1.2mol/L, the volume ratio of hydrazine hydrate in the mixed solution is 2.0%, the control reaction temperature is 85 ℃, and the leachate is obtained by filtration and washing after the reaction for 120min. and leaching residue. The obtained leaching slag was dried and weighed 0.47 g, and its main components were (%) in weight percentage: Li 1.87, Ni 33.88, Co 13.77, Mn 17.44, Fe 2.86, Al0.93, Cu 0.52. The leaching rates of lithium, nickel, cobalt, manganese, iron, aluminum and copper were 96.81%, 89.16%, 87.94%, 87.99%, 0.41%, 88.16% and 2.01%, respectively.

Take 100mL of the above-mentioned leaching solution for pH adjustment, gradually add sodium hydroxide and hydrochloric acid, adjust the pH value of the solution to 8.06, and add it to the extractant according to the O/A ratio of 2, wherein the volume fraction of Versatic 911 is 20%, and the sulfonated kerosene is 20%. The volume of the solution is 80%, the reaction temperature is controlled to be 30°C, and the raffinate and the cobalt organic phase are obtained by extraction and separation after the reaction for 5 minutes. The cobalt organic phase is subjected to three-stage countercurrent extraction, the concentration of cobalt in the obtained extract is 0.05 g/L, and the extraction rate of cobalt is 99.11% respectively.

Example 2

Waste ternary lithium-ion battery powder, its main components are (%): Li 5.13, Ni 28.80, Co 11.40, Mn14.78, Fe 0.21, Al 0.60, Cu 0.03, C 1.81; industrial grade oxygen, of which O ₂ content ≥ 99.5%; technical grade ammonium chloride, of which NH ₄ Cl content ≥ 99.5%; technical grade ammonia water, of which NH ₃ ·H ₂ O content is 25-28%; technical grade hydrazine hydrate, of which N ₂ H ₄ ·H ₂ O The content is 80%, industrial grade sodium hydroxide, of which NaOH ≥ 96%; industrial grade hydrochloric acid, of which HCl content is 36-38%; industrial grade Versatic 911, of which Versatic 911 content ≥ 99%.

Weigh 100.00g of the waste ternary lithium-ion battery powder of the above-mentioned components, add it to the quartz crucible, place the quartz crucible in the roasting furnace, seal the roasting furnace and start to introduce oxygen, and control the oxygen flow rate to be introduced to be 500mL/min, normal temperature After being fed with oxygen for 20 min, the roasting furnace was heated to 650° C. After 90 min of reaction, the temperature was cooled down. When the temperature in the furnace was lowered to normal temperature, the feeding of oxygen was stopped, and the roasting furnace was opened to obtain 97.92 g of a roasting product, wherein the main components were by weight. The percentages are expressed as (%): Li 5.24, Ni 29.41, Co 11.64, Mn 15.09, Fe 0.22, Al 0.61, Cu 0.03, C 0.01. The volatilization rate of carbon was 99.45%.

Get gained roasting product 15g, be 8:1 join in the mixed solution of ammonia-ammonium sulfate and hydrazine hydrate according to liquid-solid ratio (the ratio of liquid volume mL and solid weight g), wherein the concentration of ammonium sulfate in mixed solution is 4.0 mol/L, the concentration of ammonia water in the mixed solution is 2.0 mol/L, the volume ratio of hydrazine hydrate in the mixed solution is 3.0%, the control reaction temperature is 95 ° C, and the leaching solution and leaching solution are obtained by filtration and washing after the reaction for 90 min. scum. The obtained leaching slag was dried and weighed 2.11 g, and its main components were (%) in weight percentage: Li 1.26, Ni 23.81, Co 10.62, Mn 13.45, Fe 1.89, Al0.06, Cu 0.21. The leaching rates of lithium, nickel, cobalt, manganese, iron, aluminum and copper were 96.61%, 88.61%, 87.17%, 87.46%, 1.29%, 87.32% and 1.73%, respectively.

Take 100mL of the above-mentioned leaching solution for pH adjustment, gradually add sodium hydroxide or hydrochloric acid, adjust the pH value of the solution to 7.20, and add it to the extractant according to the O/A ratio of 1.5, wherein the volume fraction of Versatic 911 is 25%, and the sulfonated kerosene is 25%. The volume of the solution is 75%, and the reaction temperature is controlled to be 20° C. After 15 min of reaction, the raffinate and the cobalt organic phase are obtained by separation. The cobalt organic phase is subjected to three-stage countercurrent extraction, and the concentration of cobalt in the obtained extract is 0.06 g/L. The extraction rate of cobalt was 98.94%.

Claims (3)

1. a method for reclaiming valuable metal in waste and old ternary lithium ion battery positive electrode material, is characterized in that, comprises the following steps: (1) Oxidative roasting Oxidative roasting and decarburization of waste ternary lithium ion battery cathode material in oxygen atmosphere: first put waste ternary lithium ion battery powder into a pit furnace, and put it into the well furnace at a speed of 100-500mL/min at room temperature Continue to feed oxygen for 10 to 30 minutes, then raise the temperature in the furnace to 500 to 700 °C, and bake for 30 to 150 minutes. The carbon in the waste ternary lithium ion battery powder enters the subsequent absorption bottle in the form of carbon dioxide. After the reaction is completed, cool down and wait for the furnace After the inner temperature is lowered to normal temperature, the oxygen is turned off to obtain the calcined product; (2) Reductive leaching The obtained roasting product is added to the mixed solution of ammonia water-ammonium chloride and hydrazine hydrate according to the liquid-solid ratio, that is, the ratio of liquid volume mL to solid weight g, in the range of 2 to 10:1, and the concentration of ammonium chloride in the mixed solution It is 1.0～5.0mol/L, the concentration of ammonia water in the mixed solution is 0.40～2.0mol/L, the volume ratio of hydrazine hydrate in the mixed solution is 1.0～5.0%, the control reaction temperature is 55～95 ℃, the reaction After 30 to 150 minutes, the leaching residue and the leaching solution containing lithium, nickel, cobalt, manganese, iron, aluminum and copper are obtained by filtering and washing; (3) Extraction and separation The obtained leaching solution is adjusted to pH value, and the pH value of the leaching solution is adjusted to be 6 to 10. According to the O/A ratio of 0.5 to 2.5, it is added to the extraction agent, and the volume fraction of Versatic 911 in the extraction agent is 5 to 25%. The volume fraction is 65-95%, the temperature is controlled at 20-40° C., the raffinate and the organic phase are separated after the reaction for 5-25 minutes, and the cobalt chloride solution is obtained after the organic phase is back-extracted. 2. the method for reclaiming valuable metal in waste ternary lithium ion battery positive electrode material as claimed in claim 1, it is characterized in that described oxygen, ammonium chloride, ammoniacal liquor, hydrazine hydrate and extraction agent Versatic 911 are technical grade reagents . 3. The method for recovering valuable metals in the positive electrode material of waste and old ternary lithium ion batteries as claimed in claim 1, it is characterized in that: described waste and old ternary lithium ion battery powder materials, the mass content percentage range of valuable metals It is: Li 5.0-10.0, Ni 25.0-35.0, Co 10.0-20.0, Mn 10.0-20.0, Fe 0.1-1.0, Al 0.1-1.0, Cu0.01-1.0, C 1.0-5.0.

Images